Do you worry that talking on your mobile phone will cause a brain tumor?

Yes I worry, but I haven’t bothered to find out what the truth is. Procrastinating in order not risk finding that it is harmful, mainly because I WANT to use my mobile. My unprofessional and unfounded guess is that it does not.

I should NOT have read the referenced article.

No.
To do that, the electromagnetic radiation would have to be strong enough to ionise the DNA, e.g. be powerful enough to displace electrons within the molecule, thus cause structural damage to it by dissolving molecular bonds. Which the 0815 signal from a cellphone just isn’t.
The polonium contained in tobacco on the other hand, emits strong enough radiation to do that.

And according to this table , if I understand it correctly, Humans themselves have an almost 4 times as large level of internal ionising radiation as consumer products, which I think includes cellphones.

No, I just avoid talking on it for a long period of time. I don’t like talking on the phone alot anyways.

Yes. I’m also afraid that the Earth will float into a photon wave belt sometime mid-December, 2012, causing a mass shift in human consciousness.

Snarky remarks aside, don’t fret this. As @ragingloli has pointed out, the radiation emitted from radiation is incredibly weak. You’ll be fine.

Not in the least. I’d probably be hit by a bus first from talking or texting on my mobile without paying attention to traffic before the ions got to me. Which is why I don’t talk or text at crosswalks!

In addition to @ragingloli‘s excellent answers, I’d like to point out the difference between thermal radiation and ionizing radiation. Microwaves (thermal radiation) cook your food by heating it up, because their wavelength makes them good at shaking water molecules around. X-Rays (ionizing radiation) have too short a wavelength to shake water molecules around, but they are good at shaking bits off other molecules, like your DNA, which leads to all sorts of horrible things.

Radio waves are in the thermal category. You can get burned from standing next to powerful radio transmitters, which is why cell phone towers are shut down before Verizon’s service man climbs up to fish out stray pigeons. Thermal radiation won’t give you cancer, it’ll just cook you. But the radios in your cell phone are far, far too low-power to cook you.

How Stuff Works has a nice writeup that says substantially what I just said. (But with pictures!)

That link sounds just like a study I read about a couple of years ago that followed cell phone users for 10 years (the longest study of it’s kind) in some European country (Sweden, perhaps?). In the study, they found a higher incidence of brain tumors those who were frequent cell phone users.

I don’t worry about this because I don’t use my cell phone much. I make it a point to only use it when I really need to.